Effects of Lactic Acid and Sodium Pyrrolidone Carboxylic Acid on the Irritated Skin Reaction Induced by Sodium Lauryl Sulphate Patch Testing of Normal Persons and Atopic Dermatitis Patients / 대한피부과학회지

BACKGROUND: Natural moisturizing factors such as sodium pyrrolidone carboxylic acid and lactic acid may play an important role in increasing the moisture retention of isolated stratum corneum and reducing the incidence of dry and flaky skin in vivo. Although the precise mechanism of surfactant irritancy is not fully understood, it has been suggested that barrier dysfunction of stratum corneum by surfactants results in skin changes such as scaling, erythema, and even fissuring. OBJECTIVE: We evaluated the effect of sodium pyrrolidone carboxylic acid(NaPCA) and lactic acid(LA) with several non-invasive measuring methods in the irritated skin reaction induced by sodium lauryl sulphate (SLS) in normal persons and atopic dermatitis patients. METHODS: After skin irritation for 24 hours with patch test of 1% SLS on five volar sites of right forearm, we applied nothing(A), 3% LA+3% NaPCA(B), 3% LA(C), 3% NaPCA(D), and vehi cle(E) twice a day respectively. Visual score, transepidermal water loss(TEWL), water holding capa city(WHC), and erythema index were measured at 30 min, 24hr, 48hr and 72hr after patch removal. RESULTS: 1. After 72hr, the visual scores of B and C were significantly lower than that of A(control) in atopic dermatitis patients, and that of C in normal persons was significantly lower than that of A, D, and E. 2. TEWL values of B and C in both the normal (after 72hr) and atopic dermatitis group (after 48hr and 72hr) were significantly lower than that of A. 3. WHC values of B, C, D in both the normal and atopic dermatitis group were significantly higher than that of A after 48hr and 72hr. 4. After 72hr, erythema indices by Mexameter of B, C, and D in both the normal and atopic dermatitis group were significantly lower than that of A and values of C were significantly lower than that of E. In the atopic dermatitis group, values of D were also significantly lower than that of E. 5. The mean visual score was significantly correlated with TEWL value and erythema index of Mexameter (r=0.58, r=0.64) and the TEWL value was significantly correlated with erythema index of Mexameter (r=0.64). CONCLUSION: These results suggest that topical application of a moisturizing factor might improve the surfactant-induced disruption of permeability barrier with improvement of the water holding capacity of the stratum corneum.

The Study on the Effect of Six Soaps on Cutaneous Irritation Measured by Noninvasive Technique / 대한피부과학회지

BACKGROUND: Soaps are the most widely used body cleanser and sometimes cause irritation of the skin. OBJECTIVE: Our purpose was to compare the skin irritancy of 6 soaps using noninvasive techniques. METHODS: The skin responses to patch test with 6 soaps were measured by visual scoring, evaporimeter and corneometer. RESULTS: The results are summarized as follows. 1. F soap was shown to cause the least irritancy measured by visual scoring and corneometer. But using evaporimeter, there were no differences in irritancy between the 6 soaps. 2. Through correlation analysis, we found that the evaluation of the evaporimeter was closely related to visual measurement. CONCLUSION: Soap irritancy can be measured by noninvasive techniques, such as the evaporimeter, corneometer, laser doppler flowmetry and visual scoring. Further study of evaluation after short and repeat contacts with soap are needed.

Site Variation of Transepidermal Water Loss Measurement on the Normal Skin of Hands in Human Volunteers

BACKGROUND: Transepidermal water loss(TEWL) measurement is widely used in monitoring the degree of skin irritation. There have been many reports of site variation of TEWL between different body sites. However, there have been no reports concerning site variation on the different parts of the hand, which is important for the evaluation of hand eczema. OBJECTIVE: This study was done to better understand site variation of TEWL on the hands. METHODS: TEWL measurement has been performed on the mid-forearm and seven different sites of the hands in 20 normal human volunteers using an evaporimeter. RESULTS: A marked site variation has been observed and high values observed on most parts of the hands compared to forearms. CONCLUSION: Site selection should be seriously considered in any kind of study concerning TEWL measurement of hands.

The Effect of pH on Sodium Lauryl Sulfate Irritancy Potential

Five volunteers received patch tests with 5% sodium lauryl sulfate (SIS) in solutions of differing pH. The irritant effect was monitored by visual scoring as well as by a laser Doppler vlelocimeter, evaporimeter, cutometer, and colorimeter. The non-invasive methods used in this study with the exception of the cutometer were effective in the evaluation of skin irritation. No significant differences in the skin responses to SIS in different pH solutions were found either clinically or by the non-invasive methods used for quantification. It was concluded that the pH of SIS is not a major factor in the degree of skin irritation produced by SIS.